Whats the white forming on bark?

[Bob]

This morning I noticed something white forming on a few pieces bark of one my Phrags. It looks like mineral deposits, but I don't see how that could be. I have five others, all being treated the same way - only distilled water, no sprays of any kind, and the only thing added is MSU.
All the others look fine. And actually this, with the exception of the "white" whatever, looks fine too. Good color, growing well, roots look fine. Any ideas? Thanks

[Cjcorner]

A picture of the white stuff might help...could be a mold.

[Bob]

[Halloamey]

Looks like mineral deposits to me. Notice how all the white formations are at the very tops of the media components. An easy test to confirm this would be to take this white deposit covered media and put it in a cup with distilled water and a few drops of vinegar if the white disappears then it is minerals. Such white spots not only result from hard water with calcium but also because of Potassium, if used in excess.

[Bob]

Looks like mineral deposits to me. Notice how all the white formations are at the very tops of the media components. An easy test to confirm this would be to take this white deposit covered media and put it in a cup with distilled water and a few drops of vinegar if the white disappears then it is minerals. Such white spots not only result from hard water with calcium but also because of Potassium, if used in excess.

I did the water & vinegar thing - the white did not disappear. I had only distilled white vinegar on hand, might that make a difference?
I've never used anything but distilled water and the liquid MSU fert. at about 3/4 of what they recommend.
I have them standing in a large tray of water about 1" deep. Could it be mold? I always have a fan on them.

[Halloamey]

The vinegar type doen't really make any difference, its just some acid to dissolve the mineral deposits. The white spots will not vanish immediately, they may need some time. But from the looks of it, it still doesn't look to me like a fungus or mold, see how it pops up randomly without any contact in between. Just remove these pieces and see what happens, If it is not bothering the plant don't worry. Your culture sounds excellent, if they re-appear take bigger photographs with some more details and we can see.

[Bob]

I let them soak for several hrs. They darken considerably but didn't disappear completely. I can still see a little "something".
When I let the water level get down to less than 1/2", they seemed to (could be my imagination) diminish. Now with the water back up to
a little over 1", I seem to notice them more. I've removed the effected pieces as you suggested.

[Halloamey]

In this picture it is very clear that they are mineral deposits, it is possible that they are sulphates or phosphates of calcium or magnesium as they will not be dissoved my the mild acid, on the other hand if it were from carbonates it could have. Calcium phosphate is my guess, just for the fun part, you could try putting it in some coke if it dissolves then it could be phosphate (Coke has Phosphoric acid which is strong enough to dissolve calcium phosphate) But if it is sulphate could try battery acid ( I don't recomend this experiment as Battery acid i.e. sulphuric acid is very dangerous)

[Bob]

I removed all pieces with white about a week ago. They haven't come back, except for 2 very small traces. It's hard to even be sure it's the same thing, they're so small. I'm soaking those in Coke. So far, after four hours, it's still there. Is it possible for anything to "leech" from the plastic trays? Thanks

[hannah]

maybe just give your plants a good old flushing out with some rain water? It definately looks like a mineral deposit to me.